Harold74

I've been struggling to set up the front derailleur on my wife's 2016 Norco Valence. Having done a fair bit of research and trouble shooting, here's my assessment of the situation:

1) The bike currently shifts marvelously in the non-cross chained gears.

2) We get significant front derailleur rub when in the small ring and the lowest two cogs at the rear.

3) We currently have just enough cable tension to make a go of it in the big ring and smallest cog combination.

4) If I add even a quarter turn worth of additional cable tension, the shifter stops engaging when attempting to come up from the low trim position.

While I've worked on a number of bikes extensively over the last few years, this is my first experience working on a modern bike with brifters. My own bikes are 2000 or older with downtube or bar end shifters and 9 speed max. On those bikes, I can hit every cog from every ring without without front derailleur rub. I'm guessing that's a function of the narrower cassettes on those bikes and manual trim up front.

So my questions are these:

A) Is it reasonable to expect that this Tiagra 4700 be able to hit any cog from either chainring without front derailleur rub?

B) If I bought a new Tiagra 4700 right shifter, is there reason to hope that might improve the situation?

C) If I bought a new 105 right shifter, is there reason to hope that might improve the situation?

My wife is a very intelligent woman but she has no interest in really understanding her gearing and, thus, being able to avoid cross chaining. She just wants it to work smoothing without having to think too hard about it. Perhaps that's not a realistic expectation on a bike like this. Hence my questions.

FWIW:

- I've attempted the setup described in the FD manual, among several other strategies.
- I recently replaced the shift cable and housing.
- I recently degreased and relubed the left shifter.
- I recently had the shifter off and shook it to listen for loose parts. I noted none.
- The internal cable routing on the Norco is a bit weird in my opinion. Internal to the downtube and sharing that space with a housed brake cable.


2016 Norco Valence Tiagra

70sSanO

There is a different setup process for the newer Shimano front shifter. My understanding is that there is a trim function to shift to the lowest cog. Getting that wrong or right impacts the shifting to the outer ring.

Although I mention this a lot, you don’t want the FD high limit screw to stop the FD movement. With STI shifters that is more of a feel good safeguard, (if correctly setup), since the shifter can only pull so much cable. The FD isn’t going anywhere after that.

John

Edit added: I also “think” there is a outer ring trim function to use in the highest/smallest cog. But I’m not sure. However, trim is your friend.

Iride01 

I think that is an unreasonable expectation as a blanket statement for all bikes. You chain stay length plays a part in this. Longer usually being better for not having rub. However it shouldn't have much rub if any. And usually only when at the extreme cross chained positions. You are aware of trim aren't you. How to use it and how to adjust a front DR properly for trim?

What is wrong with the current shifter? I wouldn't expect any improvement replacing like with like. Or even a different model and version if you haven't identified something actually wrong with the STI or shifter. Have you checked for a frayed cable in the shifter? You have to pull a inch or so out to properly check. And why are we talking about the rear when your problem is the front?

105 has been 11 speed since about 2015-2016 or there 'bouts. While you can mix the front DR and STI, don't try to make a 11 speed STI work with a 10 speed rear.

OR... is your rear 11 speed? If so, then maybe we need to ask more about what's going on and why you have 4700 stuff as the larger part of your conversation.

You have gotten the DM's from the Shimano Tech Doc Site haven't you? They'll tell you everything you need to know about install and proper adjustment. Though they use a lot of pictograms. So you have to think a little bit sometimes to be sure you understand what they are really trying to show you.

https://si.shimano.com/en/#/

delbiker1 

My only comment is the unraveling cable, it never helps.

surak

Yes 4700 can cross chain if you use the FD trim feature. But you shouldn't cross chain (I say as the friend I sold my 4700-equipped bike to uses small-small all the time on flat ground ).

KCT1986

If you have access to the Dealers Manual for the FD, then review the first few pages. There is a notice about chain rub in the small ring/small cogs. The DM's cure is to shifter to different cog (no mention of using trim). This seems to indicate that even using the trim it may be an issue.

My guess that if the set-up is proper, this is the best you can do. Teach her to use the trim positions and hope for the best.

Harold74

Thanks, all, for your help with this. I've come to accept that my shifting situation on this bike is likely as good as I can expect it to get with the current frame & mech. My spouse is just going to have to learn how to not cross chain. This has me thinking that, in the future, my wife might enjoy bikes of this sort:

1) Bar end shifting with friction shifted front derailleurs or, more likely;

2) 1X setups with no front derailleur.

To answer a few of the questions that have been posed:

- The cable isn't really unraveled. That picture was taking before I replaced the front derailleur cable and housing.

- I did indeed dial the upper limit on the derailleur down to meet the shifter stop position.

- I am aware of trim and do believe that I've set up the FD properly for that.

Harold74

That's an interesting variable that I'd not considered. I get what you're saying with that. My wife's bike at 48 cm has a 16.5" chain stay. My bikes, at around 60 cm, have 17.5" chain stays +/-. Not a huge difference there but, then, this stuff seems to be pretty sensitive to minor variations.

I'm not sure that anything is wrong with it. That's what I'm trying to parse out. The most glaring difference between the FD's performance and my expectation for its performance is this: at the max cable tension that I can run without loosing pickup from the low trim position, I still don't have enough cable tension to avoid having a little FD rub in the big-small combo. The cross chaining stuff I can accept as the lay of the land. Not being able to tension the cable enough to hit big-small cleanly seems pretty sketchy to me. When I've read other folks complain about similar issues, they tend to mention a weak spring within the shifter and/or damaged small parts within the shifter.

It's 10 speed. Tiagra 4700 all the way through.

Yes, although the cross chaining advice did not initially sink in as it now has.

Harold74

I took another look at that notice and the associated diagram after reading your comment. I agree and take comfort from that. Thanks for pointing it out.

When I initially read the DM, I guess that I optimistically took that stuff as general "don't cross chain" advice rather than a true limitation of the setup. Now I see it as you have described it.



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Iride01 

I just took a quick measure of my son's bike that came with Tiagra 4700 installed. It's chain stay is about 16- 1/8" . He didn't complain about rubbing when it was still 4700 and he doesn't complain about it now that the bike has mostly 11 speed 105 5800 on it with the exception of the crank and FD which are still Tiagra 4700. So with your chain stays being longer then chain stay length should be an issue.

However I think there will always be some amount of rub when at the extremes. Especially the big front and big rear. Shimano even puts a plastic wear plate on the inside of the cage to soften that rubbing sound. So it's not real noticeable while riding till things get quiet in the surroundings. Is this perhaps just noise you are hearing when in the bike stand and the quiet of your workshop?

You said big-small so is that the big front and the 11 tooth rear or is small in terms of gear ratio and that is the cog with the most teeth? If you meant the big front and the 11 cog on the rear, then if you are having rub on on the side of the FDR cage closest to the frame then something would seem amiss with the installation and perhaps you should go through the install and adjustment procedures in the DM's again. Don't remember for sure if the full adjustment of the cable adjustments are in the DM for the shifter or if they are in the DM for the FDR. But check both.

To me if your rub is only when at the extreme cross chained positions then it not enough to worry about for me as one won't or shouldn't be in the extreme cross chained positions very long. Maybe a minute or two at the most. Just think of the noise as encouragement to get out of that gear combo sooner.

If you do have to stay in that gear combo for extended times, then you need to think about getting a more proper gearing for the bike and that'll probably be changing both front and back rings and cassettes. Maybe even a whole new group set or bike.

Harold74

Thanks for taking the time to do that Iride01, that was kind of you.

Big ring - Big cog rubs a little and is the kind that I could live with. The larger problem is Small Ring and the two smallest cogs. The level of noise in those combos would be intolerable to me as the rider.

Small ring - small cog is the noisiest chain rub combo.

Large ring - small cog creates a minor rub but is the one that has me most questioning whether or not something might be wrong with my shifter. I feel as though I should be able to adjust things such that Large ring - small cog has no rub if I wish. That combo ought not be a cross chaining issue in my opinion. Yeah, chain line isn't perfect in that combination but it's not "extreme" either.

Iride01 

Did you ever say if your trim works correctly? You can have your FDR adjustment messed up and trim won't work when you move the trim. You also have to take out the trim on the front when you go back the other way on the rear. But trim alone probably isn't all the issue.

oldbobcat

Properly set up, Tiagra 4700 is the smoothest shifting 2x10 drivetrain Shimano ever made. It basically takes the features that make the 11-speed systems (105, Ultegra, and Dura-Ace) so slick and puts them in a 10-speed package. But setup of the front derailleur is different.

First, the default inner ring position is high trim. When you downshift from the big ring, there is one more click to get all the slack out of the cable. This was probably done to prevent throwing the chain completely over the inner ring, which sometimes happens with default low trim. Second, the converter pin position fine-tunes the pull angle of the cable. Third, cable tension is a lot tighter than what you may have been used to with earlier generations of Shimano road systems.

So, before attaching the front shift cable, put set the chain to the lowest gear combination. Adjust the low limit screw. Set the housing into the ferrules solidly, Nearly completely retract the inline adjuster. Shift to the slackest cable position. Use the white plastic alignment tool to determine the correct position of the converter pin. Basically, if the pull is too close to the pivot of the derailleur arm, shifting up will be hard because your just pulling down on the arm instead of making it pivot, and you won't get low trim. It might even feel as if you're about to break something. If it's too far off the axis of the arm, it will basically work but there won't be enough arm movement to give you low trim. It's all about the angle of the cable up to the pinch bolt--too close to axis and shifting is hard; too far from axis and there isn't enough arm movement. Sometimes I've had to try both positions to see which works better. Having settled that, pull the front derailleur cage out a couple of millimeters. You can do this with the low limit screw or by sticking a 4- or 5-mm Allen wrench between the cage and the frame. Now, pulling the cable taut with one hand, fasten it at the pinch bolt with the other. When you restore the cage to its proper position, it should (a) clear the chain properly, (b) hit the low limit screw, (c) still have a rather taut cable, and (d) still offer a millimeter of low trim. Now fine tune cable tension with the inline adjuster and the high limit screw.

Even with trim you might still get chain rub on small-small. Good. That's your sacrificial gear. You shouldn't use it because the chain is too slack anyway. There is so much redundancy in a 10-speed cassette that you will find a ratio that's close enough using the big ring. And don't sweat big-big cross-chaining. The chain is flexible enough that the pros do it all the time. I have to pay for my chains, cassettes, and chainrings, so I use it only occasionally and for short spurts, like sprinting over the top of an easy hill that suddenly got less easy.

freeranger

Found a video on setting up the 4700 FD that may be of some help-more adjustments which can be made on FDs I've worked on:
the link would not post? but looked up

Shimano Tiagra 4700 Front Derailleur Fitting Guide--the video was by Free To Cycle

found it very detailed--might help.

tomtomtom123

I had the 4700 FD, and the trim did help prevent chain rub big-small. I can't remember about small-big, because I have a 44/24 double with a 20t jump, so the chain starts rubbing on the big chainring when on small-small 8th gear (cassette) so I never tried small-smallest.

But I did have to pay attention to what gear I was in so that I could select the correct trim. I put a sticker on the dial on the right shifter to let me know when I had to trim.

Later, I swapped the FD with a SRAM yaw, which does not need trim. I still used the 4700 shifter, I simply set the cable tension so that the low trim did nothing because it's already become slack, and the high trim is blocked by the limit screw. High trim can be selected on the shifter but I think the parallelogram spring on the SRAM FD simply transfers the cable movement into more spring tension because of the limit screw doesn't allow the cage to move any further out. Now I only have to pay attention to 2 index positions and not have to worry about trim.